Interaction Forces between Mineral Aggregates and Bitumen Calculated Using the Hamaker Constant

Abstract

ABSTRACT Moisture damages to bituminous pavements leads to costly repairs. The most serious outcome of the influence of water is the loss of adhesion between binders and aggregates. This is often described as stripping. Adhesion is the ability at a molecular level of materials to stick steadfastly to one another. An alternative way of explaining the adhesion of bitumen to aggregates is presented in this paper using the Hamaker constant, a measure of the van der Waals attraction forces between two materials. The Hamaker constant is significantly lower for water as the intervening medium than for air. For the aggregates and minerals studied, the Lifshitz-van der Waals interactions contribute 65–78 percent of the ‘work of adhesion’ calculated by the acid-base method. The performance of the aggregates and minerals correlates well to Atotal where resistance to stripping data is available.